Image processing device, image projection apparatus, image processing method, recording medium, and computer data signal

• US 20050190986A1
• Filed: 02/25/2005
• Published: 09/01/2005
• Est. Priority Date: 02/27/2004
• Status: Active Grant

• Current Assignee: Casio Computer Company Limited
• Original Assignee: Casio Computer Company Limited
• Inventors: Sakurai, Keiichi
• Granted Patent: US 8,111,949 B2
• Time in Patent Office: Days
• US Class Current: 382/275
• CPC Class Codes: G06T 3/02 Affine transformations for image registration G06T3/147; for image mosaicing G06T3/4038
• CPC Class Codes: H04N 1/00283 with a television apparatus
• CPC Class Codes: H04N 1/195 the array comprising a two-dimensional array or a combination of two-dimensional arrays
• CPC Class Codes: H04N 1/387 Composing, repositioning or otherwise geometrically modifying originals
• CPC Class Codes: H04N 1/40068 Modification of image resolution, i.e. determining the values of picture elements at new relative positions H04N1/3935 takes precedence
• CPC Class Codes: H04N 2201/0436 Scanning a picture-bearing surface lying face up on a support H04N2201/0434 takes precedence; using cylindrical picture bearing surfaces H04N1/06; with manual scanning H04N1/107

Abstract

A captured image projection apparatus obtains projection parameters and image effect correction parameters from a moving image captured at a low resolution in a task different from a task in which capturing of a high-resolution still image is to be performed, when a change ceases to occur in the moving image and before the capturing of the high-resolution still image is started. The apparatus changes the scale of the obtained projection parameters from one for low-resolution image to one for high-resolution image. The apparatus applies an image conversion process and an image effect process to the captured high-resolution still image by using the projection parameters and image effect correction parameters obtained before the still image is captured. Thereby, the captured image projection apparatus shortens the time required from the capturing of the image to projection thereof.

Claims

1. An image processing device comprising:

a change determination section configured to determine whether there is any change in an image which is captured by a camera at a predetermined resolution;

a resolution setting section configured to set a first resolution in the camera as the predetermined resolution in a case where the change determination section determines that there is a change and to set a second resolution higher than the first resolution in the camera in a case where the change determination section determines that there is no change;

a correction parameter extraction section configured to extract parameters for correcting an image from the image captured by the camera at the first resolution; and

an image correction section configured to correct an image captured by the camera at the second resolution by using the parameters extracted by the correction parameter extraction section.

2. The image processing device according to claim 1, wherein

the correction parameter extraction section includes

a polygon detection section configured to detect from the image captured by the camera at the first resolution, a polygon shaping a contour of the image, and

an affine parameter obtaining section configured to obtain affine parameters from coordinates of vertexes of the polygon detected by the polygon detection section, and

the image correction section includes an inclination correction section configured to correct an inclination of the image captured by the camera at the second resolution by performing affine transformation of coordinates of each pixel included in the image by using the affine parameters obtained by the affine parameter obtaining section.

3. The image processing device according to claim 2, further comprising a scale change section configured to change scale of the affine parameters obtained by the affine parameter obtaining section from scale for the image captured at the first resolution to scale for the image captured at the second resolution, by multiplying each element of the affine parameters by a predetermined multiple.

4. The image processing device according to claim 1, wherein

the correction parameter extraction section includes

a luminance histogram generation section configured to generate a luminance histogram showing distribution of luminance in the image captured by the camera at the first resolution, by counting number of pixels included in the image for each luminance value,

a color difference histogram generation section configured to generate a color difference histogram showing distribution of color differences in the image captured by the camera at the first resolution, by counting number of pixels included in the image for each color difference, and

an image effect correction parameter obtaining section configured to obtain a maximum value, a minimum value, and a peak value of luminance from the luminance histogram generated by the luminance histogram generation section and a peak value and an average value of color difference from the color difference histogram generated by the color difference histogram generation section, thereby obtaining image effect correction parameters including the maximum value, the minimum value, and the peak value of luminance, and the peak value and the average value of color difference, and

the image correction section includes a luminance/color difference correction section configured to correct luminance and color differences of the image captured by the camera at the second resolution, by adjusting luminance and color differences of each pixel included in the image by using the image effect correction parameters obtained by the image effect correction parameter obtaining section.

5. The image processing device according to claim 1, further comprising a correction parameter extraction request section configured to request the correction parameter extraction section to extract the parameters from the image in a case where the change determination section determines that there is a change in the image.

6. The image processing device according to claim 1, wherein

the correction parameter extraction section includes a correction parameter extraction notification section configured to notify the image correction section that the parameters have been extracted from the image.

7. The image processing device according to claim 1, wherein

the correction parameter extraction section performs extraction of the parameters in a different task from a task in which change determination by the change determination section, resolution setting by the resolution setting section, and image correction by the image correction section are performed.

8. The image processing device according to claim 1, wherein

the change determination section includes an image change amount calculation section configured to calculate an amount of change in the image captured by the camera, whereby determining that there is a change in the image in a case where the amount of change in the image calculated by the image change amount calculation section is not smaller than a predetermine threshold and determining that there is no change in the image in a case where the calculated amount of change in the image is smaller than the predetermined threshold.

9. The image processing device according to claim 8, wherein

the image change amount calculation section calculates total of absolute values of differences between pixel values of respective pixels included in a previously captured image and pixel values of respective pixels included in a currently captured image, as the amount of change in the image.

10. An image projection apparatus comprising:

an image capture section configured to capture an image at a predetermined resolution;

a change determination section configured to determine whether there is any change in the image captured by the image capture section;

a resolution setting section configured to set a first resolution in the image capture section as the predetermined resolution in a case where the change determination section determines that there is a change, and to set a second resolution higher than the first resolution in the image capture section in a case where the change determination section determines that there is no change;

a correction parameter extraction section configured to extract from an image captured by the image capture section at the first resolution, parameters for correcting the image;

an image correction section configured to correct an image captured by the image capture section at the second resolution by using the parameters extracted by the correction parameter extraction section; and

a projection section configured to project the image corrected by the image correction section on a screen.

11. An image processing method comprising:

a change determining step of determining whether there is a change in an image which is captured by a camera at a predetermined resolution;

a resolution setting step of setting a first resolution in the camera as the predetermined resolution in a case where it is determined in the change determining step that there is a change, and setting a second resolution higher than the first resolution in the camera in a case where it is determined that there is no change;

a correction parameter extracting step of extracting from an image captured by the camera at the first resolution, parameters for correcting the image; and

an image correcting step of correcting an image captured by the camera at the second resolution by using the parameters extracted in the correction parameter extracting step.

12. A recording medium storing a program for controlling a computer to execute:

a change determining procedure of determining whether there is any change in an image captured by a camera at a predetermined resolution;

a resolution setting procedure of setting a first resolution in the camera as the predetermined resolution in a case where it is determined in the change determining procedure that there is a change, and setting a second resolution higher than the first resolution in the camera in a case where it is determined that there is no change;

a correction parameter extracting procedure of extracting from an image captured by the camera at the first resolution, parameters for correcting the image; and

an image correcting procedure of correcting an image captured by the camera at the second resolution by using the parameters extracted in the correction parameter extracting procedure.

13. A computer data signal embedded in a carrier wave and a representing a program for controlling a computer to execute:

a change determining procedure of determining whether there is any change in an image captured by a camera at a predetermined resolution;

a resolution setting procedure of setting a first resolution in the camera as the predetermined resolution in a case where it is determined in the change determining procedure that there is a change, and setting a second resolution higher than the first resolution in the camera in a case where it is determined that there is no change;

a correction parameter extracting procedure of extracting from an image captured by the camera at the first resolution, parameters for correcting the image; and

an image correcting procedure of correcting an image captured by the camera at the second resolution by using the parameters extracted in the correction parameter extracting procedure.